This system is still under construction in places! Even when it is done, it will only be for advanced users!
parsers
In hydrus, a parser is an object that takes a single block of HTML or JSON data (as returned by a URL) and returns many kinds of hydrus-level metadata.
Parsers are flexible and potentially quite complicated. You might like to open network->manage parsers and explore the UI as you read these pages. Check out how the default parsers already in the client work, and if you want to write a new one, see if there is something already in there that is similar--it is usually easier to duplicate an existing parser and then alter it than to create a new one from scratch every time.
There are three main components in the parsing system (click to open each component's help page):
- Formulae: Take parsable data, search it in some manner, and return 0 to n strings.
- Content Parsers: Take parsable data, apply a formula to it to get some strings, and apply a single metadata 'type' and perhaps some additional modifiers.
- Page Parsers: Take parsable data, apply content parsers to it, and return all the metadata in an appropriate structure.
Once you are comfortable with these objects, you might like to check out these walkthroughs, which create full parsers from nothing: